Process for the manufacture of color-screens.



UNITED STATES PATENT OFFICE.

CARL SPATH, F STEGLITZ, NE AR BERLIN, QERMANY, ASSIGNOR TO EASTMAN KODAK COMPANY, 01? ROCHESTER, NEW YORK, A. GORPORATION OF NEW YORK.

PROCESS FOR THE MANUFACTURE OF COLOR-SCREENS.

No Drawing.

To all whom it mag concern: Bait known that I, CARL Srlirrnchemist, a,subject of the German Emperor, re-' siding at 41 Rheinstrasse,Steg1itz,nearBer- 5 lin, Germany, have myented new and useful Improvements in Processes for the Manufacture of color Screens, of which the following is a specification.

My invention relates to .the manufacture of color screens such as are used in three according to the three fundamental colors. In manufacturing color screens of this land it has been-suggested to protect the surface of the film with a coating of a resinous or fatty substance such as for instance caoutchouc and to scratch narrow parallel lines in this protective coating by which the con- --;-verted cellulose surface is exposed. If then the film is immersed in a bath containing a suitable staining solution, only tl1ose por-- 2 5 tions of the surface are stained which are exposed by the previous removal of the pro tective coating. In order to obtain the sub sequent coloring it is necessary again to remove a part of the remaining protective 3 coating. This can be done by again scratchmg out a system of parallel lines inclinedat a suitable angle to the first system. The vresult then is a surface containing lin'es stained with the first color alternating with 5 lines consisting of alternate fields covered; I with protective substance and fields having as yet no coloring. If this film is immersed in a staining bath some provision must be made to prevent the dye changing the colorng produced by' the first bath. Then by washing in a suitable solvent the remainder of the protective coating can be removed and the film immersed for a third time in a staining bath.

I have discovered that a film stained by one dye, for instance a blue dye, is not affected by immersion in another dye for instance a green dye, if the solvent of the latter is made more dilute by the addition of t water or other suitable liquids than that of the first dyeing solution. Accordingly my invention consists in providing a converted cellulose film with a protective coating which is successively changed to expose different portions of the surface and in sucvSpecification of Letters Patent.

Application filed October 14, 1910. Serial No. 537,062.

' PatentedDec..16, 1913.

cessively immersing the film in differently colored staining baths the solvents of whic are progresslvely diluted for successive immersions.

The process can be carried out, for in- 80 stance, in the following manner: A nitrocellulose film is covered on both sides with a protective layer by dipping it into a so- 'lution of rubber in benz-ol, and in one of these layers a series of lines are scratched just deep enough to expose the cellulose surface. The film is then dipped. intoa solution ofa blue dyestuif which is for instance obtained by dissolving 2 grams of Victoria bluein 100 cubic centimeters of absolute alcohol. The film is rinsed in water in order to wash off the excess of the dye. The protective layer 1s then again out up into parallel lines preferably arranged at an angle of 90 to the direction of the first ruling, and '15 these second lines also reach only to the surface. The nitr-o-cellulose surface will be thus decomposed into blue and noncolored lines, the latter of which are alternately decomposed into protected and unprotected 80.

squares. By dipping into a solution of 2 grams of auramin and 1' ram ethyl green" in 150 cubic centimeters 0 alcohol of the unprotected parts will. be colored green,

while the-portions already colored blue will remain unaffected owin to the greater dilution of the solvent. he'remaming portions of the protective layer are then washed off from the film which now represents a screen, consisting of blue lines and green squares and the third coloring canbe ef-- fected' with red-dye stullin a still more diluted solvent. To that end is used for iiistance asolution of 2 grams of'rubin and 1 gram auramin in 150 cubic centimeters of alcohol of 60%. When the screen is treated with this stain onlythe non-colored portions will be stained. The result will therefore be a color screen consisting of blue, lines and 'green and red squares, and the non-treated protective layer is then removed from the back of the said color screen in any well known manner.

The above example may be considered as typical inasmuch as it represents a very simpic rule of proceeding. I find however that it is not equally applicable to different kinds of converted cellulose. Converted cellulose as used for photographic films differs largely. Broadly two classes can be discerned namely nitrated cellulose and acetyliz'ed cellulose. The former is usually mixed with camphor but the percentage of camphor used largely varies with different manufactures. *j I have found that the substances and concentrations mentioned above by way of an example give indifferent results unless a converted cellulose is used consisting of nitratd'cellulose with a high percentage of camphor. 'Forconverted cellulose poor in camphor I find tha'tthe pure alcoholic'solutions diluted with. water "can be greatly improved by adding acetone besides waters- As a rule-I find that'the percentage of acetone in the solvent should be increased as the amount of camphor present in the converted cellulose diminishes. With acety lized cellulose which contains no ca'mphor the ratioof the amounts of alcohol to those of acetonecan 'be diminished to zero, or

whatcomes to the same, material of this kind can betreated with dyeing solutions in pure acetone diluted with water.

As an example of dyeing solutions applicable to nitrated cellulose which is poor in camphor I give the following:

Blue ciye.'2 grams of Victoria blue are dissolved irilOQ cubic centimeters of alcohol of 95% and to 100 cubic centinietersof this solution are added 4: cubic centimeters of acetone and t cubic centimeters of water.

Green dye.2 grams of ethyl green and 2 grams of auramin are each dissolved in 4 5 100 cubic centimeters" of alcohol of 95%.

30 cubic centimeters of the first and 70 cubic centimeters of the second solution are mixed and to the mixture are added 8 cubic.

centimeters of acetone and 8 cubic centimeters of water.

Red dye.2 gramsof rubin and 2 grams of auramin are each dissolved inlOO cubic centimeters of alcohol of 95%. 50 cubic centimeters of the first and 50 cubic centimeters of the second solution are mixed and to the mixture are added-10 cubic centimeters of acetone and 12 cubic centimeters of water.

As an example of dyeing solutions applicable to acctylized cellulose I-give the fol quence of coloring may be modified. In the same way any combination of three fundamental colors can be selected which is suitable for reproducing natural colors in color photography.

If color screens of this kind are to be manufactured in larger quantities it is not convenient to produce the unprotected parts of the surface to be stained by first covering it with a' protective coating and then removing parts of the coating by scraping or scratching out lines. It is preferable in stead to'print lines'or any other suitable patterns on the film by means of a cylinder suitably engraved, as is well known in theart. In this case the process must be slightly modified. For instance a system of straight parallel lines of some fatty or resinous substance adapted toprotect the surface covered thereby againstalcoholic and other solutions of dyes may first be printed on the surface. Then the parallel lines remaining unprotected may be stained by immersion in a blue dye. Then the protective lines may be washed off in benzol or any other suitable solvent. The product of this first series of operations is a screen having alternate blue and unstained parallel lines. in On this may be printeda' second system of protective lines crossing the blue lines at any suitable angle and the film may then be immersed in,

a green dye prepared according to my invention as described above, so as to stain the uncolored parts of the exposed l nes but not to affect the parts already stained blue. The second system of protective lines is then again washed off and the result of this second operation is a film covered with blue lines and green squa. es alternately. This is finally immersed in a third dye solution pre pared as described above and after washing and drying the screen will then be ready for use. It will be understood that it is within my invention to apply two of the colors, say green and blue, in the manner described, a third color having been applied previously, or being applied subsequently, as may be desired. A

' Having now particularly described and ascertained the nature of my said invention and in what manner the same is'to be performed, I declare that what I claim is 1-.

l. The improvement in the process vfor nninufacturing color screens for colorphotography on converted cellulose films by means of a protective coating'which is progressively changed'to expose different parts of the surface to the effect of staining solutions which improvement consists in successively immersing the film in the different staining solutions, the solvents of which are progressively diluted.

2. The improvement in the process for manufacturing converted cellulose color screen films by means of a protective coating which is changed to expose difierent parts of the surface for successive staining oenaai operations which improvement consists in successively immersing the film in the differ ent staining solutions the solvents of Which contain progressively increasing percentages of Water.

3. The improvement in the process for manufacturing nitro-cellulose color screen films by means of a protective coating that is changed to expose different parts of the surface for successive staining operations which improvement consists in successively immersing the film in alcoholic staining solutions of different colors using progressively increasing percentages of acetone and Water for successive coloring baths, the ratio of the quantities of acetone to those of alcohol be ing increased as the percentage of eamphor contained in the intro-cellulose is diminished.

l. A process for manufacturing nitrocellulose color screen films which process consists in partially covering the film With a protective coating immersing in a blue staining solution, the solvent oil which is a mixture of alcohol, acetone and Water, changing the protective coating so as to expose ditterent parts of the surface and immersing in a green staining solution the solvent of which contains a larger percentage of acetone and Water than the preceding, removin the remainder of the protective coating and immersing in a red staining solution the solvent of which contains a still larger percentage of acetone and Water than the first mentioned one, the ratio of the percentage of alcohol to that of acetone being decreased according to the percentage of camphor contained in the film.

5. A process for manufacturing nitrocellulose color screen films which process consists in prii'iting parallel lines of a protective resist on the surface of the film, immersing in a solution of a blue staining substance in alcohol, acetone and Water, removing the protective printing by Washing in a solvent,

printing a second system of parallel lines of protective substance inclined toward the first system on the surface of the film, inimersing the film in a solution of a green staining substance in alcohol, acetone and water the percentage of acetone and water employed being greater than with the blue solution, removing the protective printing by Washing in a solvent and finally immersing in a solution of a red staining substance in alcohol, acetone and water, the percentage of acetone and water in the solvent being greater than that used with the green staining solution, the percentage of acetone employed in the solvents being increased as the percentage of camphor contained in the film diminishes.

6. A process for manufacturing three color screens on films of converted cellulose which process consists in printing on the surface of the film parallel lines of a protective substance, immersing the film in a solution olf a blue coloring substance in ace tone and water, removing the protective printing by washing in a solvent, printing a second system of lines of a protective sub stance inclined to the first system, in'unersing in a solution of a green staining substance in acetone and alter the percentage of Water being larger than with the blue solution, removing the protective printing by Washing in a solvent and finally in'nnersing the film in a solution of a red staining substance in acetone and Water the percentage 01'' Water being greater than that oi the green staining solution.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

CiltltL SPA/Fl l1.

l l 'itnesses ll ornnimn Hanna, HENRY llasrnn. 

